I clearly have an appetite for this sort of thing and got another valuable earful last Friday when Dr Candace Scott came from St. Lawrence College, Kingston, Ontario to visit The Institute and gave us a talk about her work as a conservation biologist. She has worked with lions Panthera leo and hyaenas Hyaena brunnea, but the love of her scientific life are the rhinoceroses, especially those in Africa. As with two species of elephant that turned out to be three, when I was growing up any fule kno that there were two species of African rhino: black and white. We all knew that white rhinos weren't so colored - 'white' was a corruption of Dutch/Afrikaans wijd/wyd which referred to their shovel-like grazer 's upper lip. Black rhinos had a pokey-pointy upper lip more suitable for browsing foliage higher than the knees. Scott has used the tools of molecular genetics to identify signature DNA variants which distinguish the African rhinos from each other and from their more distant cousins in Asia. Dramatis personnae:
- White rhinos Ceratotherium simum with subspecies
- NWR Northern White Rhinos C. simum simum critically endangered, probably extinct in the wild; original range where Uganda, DRCongo and [S]Sudan now meet
- SWR Southern White Rhinos C. simum cottoni doing okay down South Africa way
- Black rhinos Diceros bicornis with subspecies
- D. bicornis bicornis
- D. bicornis michaeli
- D. bicornis minor
- Note Wikipedia claims at least 5 extant subspecies.
- Indian rhino Rhinoceros unicornis
- Sumatran rhino Dicerorhinus sumatrensis
- Javan rhino Rhinoceros sondaicus
Candace Scott, has worked for many years in quite primitive conditions to obtain reproducible data that separates, or doesn't, the various sub-species [MSc thesis]. She is not the first person to attempt this work, but she found that previous studies yielded very noisy results: it was hard to assign an individual rhino to its morphological category (species/subspecies) based on the genetic markers the earlier scientists had developed. On the contrary, her discrimination is commendably crisp and shows [Above] two interesting findings.
- It is impossible to distinguish D. bicornis bicornis DBB from D. bicornis minor DBMIN which are intercalated in the bottom right corner of the multivariate statistical analysis. So they should be treated as equivalent and interchangeable. D. bicornis michaeli DBMIC, OTOH, is quite distinct, indeed as distinct as the two Asian good species Rhinoceros sondaicus JR and Dicerorhinus sumatrensis SR.
- Likewise , the two subspecies of white rhino SWR and NWR should be promoted to separate species, like the elephants before them.